In rolling piston or fixed vane compressors, the annular roller or piston is moved by the eccentric journal on the shaft such that the cylindrical surface has a very small clearance with the bore of the cylinder. In a single cylinder rotary compressor the ends of the annular roller or piston are, typically, in sealing contact with the pump and motor bearings, respectively. In a twin cylinder rolling piston compressor, the eccentric journals, and therefore the annular rollers, are 180.degree. out of phase to provide a balanced operation. Also, in a twin cylinder rolling piston compressor, two additional facing ends of the annular rollers must be sealed. The sealing of the four axially spaced, moving ends of the annular rollers presents assembly and alignment problems.